Xenarthra Flashcards
what does Arthra mean
strange joint
what train defines Xenarthra
Accessory Zygapophyes on the lumber vertebra.
what are the characteristics of early Xenarthra
2 additional zygapophysis on the lateral surface of their lumbar and thoracic vertebrae.
what is the purpose of the Zygapophysis on the spine
strengthens the spine but restricts movement side to side.
what are the 2 orders found within Xenarthra
Pilosa, cingulata
Evolutionary order
- started as a sloth like, leaf eating cellulose fermenter
- off shoots then included
- Armadillos that split off first and were successful groud scavengers. then sloths and anteaters split off later and both are for difficult food types.
Characteristics of living Xenartherans
- backbone flexibility is one dimensional (left - right)
- Teeth mostly absent, if present lack enamel.
- smell is the most emphasized sense
-Exploit difficult food sources - extreme specialist
- Try to save thermoregulatory energy
how do xenarthrans try to save thermoregulatory energy
they have low body temps and/or heterothery. they adapt their behavior, choice of habitat.
what is special of xenarthrans metabolism
they have low basal rates for their size when compared to other mammals. they have the lowest of any therian.
what are the consequences of Xenartherans metabolism?
- Low reproduction rate
- Slow movement
- Extended parental care
- Lower Body temp
general characteristics of order Pilosa (Anteaters)
- Powerful front legs each having a singular enlarged claw to slash into ant and termite mounds.
- No teeth w/ elongated rostra with a long sticky tongue.
- thickening of the pyloric region of the stomach to serve as a place for the grinding of chitinous exoskeletons.
Type one Anteaters (small bodied and arboreal)
- Silky anteater
- entirely nocturnal
- eats around 5000 ants per day
- male overlap in territorial pattern.
Type two Anteaters (Medium sized part arboreal and part terrestrial)
- Genus Tamandua
- Found in C. America and S. Mexico
- Eats ants and termites and needs 9000 a day
- used tripod defense
- 1 baby w/extensive maternal care for up to 1 year
- most common
Type three (Large and arboreal)
- 2 genera, 4 species
- Giant anteaters
- Diurnal and terrestrial
- live in NW Argentina, S. America E of the Andes to C. America.
- Females bear one young per year and nurse for 6 months and carries on back for one year.
- Male overlap territory
- Need 14,000 - 28,000 insects per day.
- Typically feed from 100 colonies per day eating about 200 for each as to not deplete supply.
Order Pilosa (Sloths) taxonomic diversity
- used to be greater with more than 60 generas.
- 2 and 3 toes sloths developed convergently
- All extant species are tree sloths.
